The Earth's magnetospheric cusp is a key region for transferring the solar wind energy, mass, and momentum into the Earth's magnetosphere. Recently, a broad and dynamic region of radiation in the geospace is discovered which is centered at the Earth's magnetospheric cusp. The size of the region is up to 10.5Re (Earth radii) in the depth, the size is 6Re in the latitudinal direction and is bigger than 10Re in the longitudinal direction at an altitude of 7-8Re. When spacecraft was crossing through the new region of radiation, it observed orders of magnetude enhancements for both electromagnetic fluctuations and energetic charged particle intensities. When solar wind charged particles access the cusp, the diamagnetic effect further tears wide and deep magneticholes in the magnetosphere and further transfer the solar wind energy into the electromagnetic fluctuation power. The strong electric field fluctuations could efficiently energize the cusp charged particles by cyclotron resonant acceleration, resulting in a broad and dynamic region of radiation centered at the cusp. The ion phase space densities in the region of radiation could be two orders of magnitude higher than that in the outer radiation belt at a given magnetic moment. The region of radiation is observed on both open and closed geomagnetic field lines. It could extend to low-latitude, overlapping with part of the outer radiation belt and providing a direct particle source for the outer radiation belt.